17 jewels - and beating at 18,800 vibrations/hour, the movement is rated at 46 hours of power reserve. I took two days off with the watch wound on my desk to confirm this power-reserve rating - and just it was slightly north of 46 hours for me, your mileage may vary.
The timekeeping has been strong with +6 seconds over the first week.
And back to the case itself. Unlike a few modern half-hunters I have seen out there, the clasp closes and releases with very reassuring clicks. The action is smooth and solid, nothing flimsy or half-way about it.
Halfway done, so far so good!